The heme-binding properties of prostaglandin synthetase from sheep vesicular gland.
Purified, apoprostaglandin synthetase was prepared from sheep vesicular gland and studied in terms of its heme-binding properties. The enzyme binds a single heme group per enzyme monomer, Mr = 70,000. When reconstituted with heme, the enzyme has an absorption maximum at 412 nm and an absorption coefficient, epsilon 412 nm, of 120 mM-1 cm-1. The binding of heme to the apoenzyme was accompanied by a proportional increase in enzyme activity up to the point of heme-binding saturation. This reconstituted holoenzyme forms prostaglandin H2 from arachidonate. We conclude that prostaglandin synthetase possesses the heme-binding properties of a "typical" heme protein and that a single heme group mediates both the oxygenase and the peroxidase activities of the enzyme.
D000818:Animals; D001665:Binding Sites; D006418:Heme / Q000378:metabolism*; D046911:Macromolecular Substances; D008297:Male; D008970:Molecular Weight; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011485:Protein Binding; D012669:Seminal Vesicles / Q000201:enzymology*; D012756:Sheep; D013053:Spectrophotometry
D046911:Macromolecular Substances; D006418:Heme; D011451:Prostaglandin-Endoperoxide Synthases